president obama vows to bring r whoever is responsible to justice. do not know who did this or why and people shouldn't jump to conclusions before wenc have alllu the facts, but make o mistake, we will get to the gett bottom of this. and we will find out who did did this, we will find out why theyy did this. this. >> three people were killed in the explosions including an 8-year-old boy. more than 140 people were also injured, 17 of them critically.t >>> there's heightened security at a number of high risk locations throughout the drisk district as a precaution. that includes the white houseite and today's emancipation paradea melanie alnwick is outside of the white house.house. melanie. >> reporter: noticeable noti security throughout the area including at international inten airport and of course, here at the white house alonghous pennsylvania avenue.pennsylvan thiae u.s. see vet service has expanned its security perimeteri but not because of any sesk intellencany specificintelligen. a secret service spokesperson saying the action taken out oftf an